Electrical control apparatus



March 30, 1943. 1-1. F. ELLIOTT ELECTRICAL CONTROL APPARATUS 8 Shegacs-Sheet 1 Filed May 20, 1940 v INVENTOR. hnxeom F ELL/07'7" BY Zia ham ATTORNEY.

Mar c h 30, 1943. H, ELLIOTT 2,315,191

ELECTRICAL CONTROL APPARATUS Filed May 20, 1940 8 Sheets-Sheet 2 9 Fig. 5

March 30, 1943. ELLIOTT 2,315,191

ELECTRICAL CONTROL APPARATUS Filed May 20, 1940 8 Sheets-Sheet 3 I INVENTOR. fineow F ELL/arr A TTORNEY.

ELECTRICAL CONTROL APPARATUS a Sh-et -Sh--c 4 Filed May 20, 1940 c S CO 5 1 INVENTOR.

li /P040 F. El. 1. I077 MMKW ATTORNEY.

March 1 H. F. ELLIOTT v ELECTRICAL CONTROL APPARATUS Filed May 20, 1940 8 Sheets-Sheet 5 v INVENTOR. fin/vow E ELL/07'7" ATTORNEY.

March 30, 1943. H. F. ELLIOTT 2,315,191

ELECTRICAL CONTROL APPARATUS Filed May'20, 1940 '8 Sheets-Sheet 6 l l: 1 'E {I 3 l 1 5 j r B5 Q Q I 00 ||1 191 I i II" I 1 I O I I I I I INVENTOR. fin/$ 01.0 E 5 14/077" ATTORNEY.

March 30, 1943. H. F. ELLIOTT ELECTRICAL CONTROL APPARATUS 8 Sheets-Sheet 7 Filed May 20, 1940 INVENTOR. flmozo fi ELL/Q77 BY W X M ATTOIANEY.

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March 30, 1943. H. ELLIOTT 2,315,191

ELECTRICAL CONTROL APPARATUS Filed May 20, 1940 8 Sheets-Sheet 8 a 590. 1* .:ae 0 139 Fig. 16

ATTORNEY.

Patented Mar. 30, 1943 ELECTRICAL CONTROL APPARATUS Harold F. Elliott, Chicago, Ill. Application May 20, 1940, Serial No. 336,083

24 Claims.

This invention relates to control apparatus and in particular to an automatic tuning device for radio receiving apparatus. This application is a continuation in part of application Serial No. 82,494, filed May 29, 1936, and issued on May 21, 1940, as Patent No. 2,201,162.

It is an object of this invention to provide an improved automatic tuning device for radio receiving apparatus.

A further object of this invention is to provide simple, inexpensive. rapid, and accurate means for tuning radio sets by electrical control from local push buttons, remote push buttons, time control clocks and other circuit initiating means, when such means are connected either separately or in parallel.

A still further object of this invention is to provide a tuning device. which may be used with equal efficiency in a tuning system with substantially any type of mechanism for changing fre-' quencies, although it is particularly adaptable to a trimmer condenser tuning device.

Another object of this invention is to provide an automatic tuning device which is of simple, compact and rugged construction and comprised of parts which are readily standardized and formed by punching or stamping operations to reduce manufacturing costs to a minimum.

A feature of this invention is found in the provision of a relay for tuning radio sets in which the mechanical arrangement of the magnets, arma-- tures, switches and interlocks provides for their operation by relatively small magnetic forces, whereby to provide for the efficient application of small, low cost magnets.

A further feature of this invention is found in the provision of a power relay which is operatively associated with each of a plurality of control stations to provide for an automatic operation of the radio receiving set whenever a station button is pressed and to stop such operation on the pressing of an off button.

A still further feature of this invention is the provision of an automatic tuning device having an armature for operating the switch contacts of a-particular circuit, in which as many switches as desired may be operated by each armature, the

switches being constructed integrally'with trim-- mers or connected to other tuning means so as to permit great flexibility in the use of tuning circuits and types of tuning means.

Another feature is found in the provision of automatic tuning apparatus in which a single latch is arranged to effect a selective releasable locking of the tuning circuits and the power this invention will appear from the following description when taken in connection with the accompanying drawings, in which:

Fig. 1 is a plan view of a preferred embodiment of the invention;

Fig. 2 is a front elevational view of the same;

Fig. 3 is an enlarged end elevation looking toward the left in Fig. 2;

Fig. 3a is a detail fragmentary view of the latch and associated armature of the trip relay;

Fig. 4 is an enlarged end elevation toward the right in Fig. 2;

Fig. 5 is a fragmentary plan view of a modified form of the invention;

Fig. 6 is a fragmentary sectional view as seen along the line 6-6 of Fig. 5;

Figs. '7, 8 and 9 illustrate in detail, but in looking changed positions, a multiple contact switch of a type used in the embodiment of Fig. 5;

- Fig. 10 illustrates in detail a single contact switch of a type utilized in the embodiment of Fig. 5;

Fig. 11 is a fragmentary plan view, with parts thereof in section, illustrating yet another form of the invention;

Fig. 12 is a fragmentary front elevation showing the arrangement of the power relay and tuning switches in the embodiment of Fig. 11;

Fig. 13 is a sectional view as seen along the line Iii-13 of Fig. 12; i

Fig. 14 is a sectional view taken along the line 14- of Fig. 12;

Fig. 15 is a sectional view taken approximately along the line i5l5 in Fig. 12;

Fig. 1 6 is a detailed showing of a tuning switch The present invention provides a relay struc- (I ture in which a tuning magnet, an armature and one or more pairs of contacts operated from the armature by an insulating member are included with each control station. An interlock, or latch. operated by the tuning magnets, or by a separate magnet in series in the common return circuit of the tuning magnets, provides for holding the tuning magnet last operated in closed position and 5 for releasing previously operated tuning magnets. The interlock also holds a power switch or relay closed whenever a tuning magnet is energized and opens the switch when the oil circuit is energized. The power switch may be operated by a magnet in the common return circuit of the tuning magnets or by a separate circuit controlled by switches operated with the tuning switches.

With reference to Figs. 1 to 4, the preferred form of the invention includes an L-shaped supl5 porting frame for a plurality of magnets 2m- 2ij, inclusive, which are in longitudinal alignment and operatively associated with corresponding longitudinally aligned armatures 2211-22}, inclusive, respectively. The vertical extending leg 20 portion 23 of the combination yoke and supporting member 20 is of a length substantially equal to the length of the magnets, for a purpose to be emlained. Although the tuner is shown as comprised of a power relay 24, a trip or release relay 25 2G, and four control stations or switches 21a, 21b, 21c, and 2311, it is to be understood, that any desired number of control stations may be used. Since each magnet and armature is of substantially the same construction, only one corresponding set thereof such as 2| a and 22a of con trol switch 21a will now be described.

The armature 2211 (Fig. 3) is provided near its end 28a with an elongated aperture or slot 29a which is adapted to receive therethrough one of a plurality f corresponding extending fingers or projections 3i which are integrally formed with a longitudinally extending mounting plate 32 having a bent side portion 33; the portion 33 and the bent end portion 3| of each finger 3| providing for a mounting plate of substantially U-shape. The fingers 3! are substantially co-extensive in length with the leg portion 23 of the supporting frame or yoke 20 and are attached to such leg portion by screws 31 or like means. It is thus seen that the armature 22a is pivotally supported' on a finger 3! in a manner to be movable into and out of contacting engagement with its associated magnet 2ia. Because of the mechanical assembly oi the magnets, the pole pieces therefor, and the yoke or supporting frame for the magnets, the upper face of the leg portion 23, and the pole face may all be simultaneously ground after assembly so that these faces are in absolute alignment and a full face contact with the armature at all these points is assured. This contributes to quiet operation on alternating current. The action of the magnet to attract the armature is opposed by the action of a spring 38a, which is secured at one end to the armature end 28a and 0 at its opposite end to the bent end portion 39 of a corresponding finger 3| and is adapted to normally exert a pressure in a direction to maintain the armature 22a out of engagement with the magnet 2la.

The armature 22a, after de-energization of the magnet 2ia, is locked in substantially its engaging position with the magnet by a non-magnetic latching plate or interlocking member 39 which is pivotally connected to the supporting frame 29 by T-shaped holding members 4| extendin through slots in the plate 39 and secured to the free end of the frame leg member 42 as by screws 45 or like means. The latching plate 39 is provided in a suitable stamping metal and is formed at its free side with a holding lip 43 which is adapted for sliding engagement over a portion of its length with the armature end a to eifect a gradual lifting of the plate 39 against the action of the springs 43 prior to the snap engagement of the lip 43 with the armature. Each of the springs 43 is arranged in tension between the latch 39 and a transversely extending bracket 41 which is attached to the opposite ends of the supporting frame 29. Suitably mounted in the corresponding ends 43 of the brackets is a non-magnetic bar 49, the bar acting as a stop for the armature 2|a to define one or its two operating positions.

The armature 22f associated with the power rclay 24 and the 'armatures of the control switches 210-2141 are of substantially flat form over their entire length so as to be held by the lip 43 when they are in a contacting positionwith their respective magnets. Since the tuning switches Tia-21d are separately operated the movement of an actuated armature into an engaging position with its energized magnet will move the-latch plate 39 outwardly, prior to contacting the magnet, to release any previously actuated armatures. This is shown clearly in Figs. 3 and 4 with the holding lip 43 acting as a cam as an armature is pulled from full line position to dotted line position. An energization of one of the magnets 2ia-2ld, therefore, not only actuates an armature to effect a closing of its corresponding tuning circuit, but also actuates such armature to pivot the latch member 39 out of its engaging position with any previously actuated armature to open any previously closed tuning circuit.

In one commercial application of this embodiment trimmer condensers, Sic-Sid are provided for each of the tuning switches 21a21d, respectively, the condensers being suitably arranged in longitudinal alignment on a supporting rack 52 which is secured to the bent portion 33 of the mounting plate 32 so that a condenser is located substantially opposite a corresponding switch armature. The condensers 5la-5id are adjusted in a well known manner, by adjusting screws 53a- 53d, respectively, and are suitably insulated from the plate 32 and rack 52. Each condenser Sim-Sid is comprised of two related portions Ella-50d, respectively, which are mounted on parallel longitudinally extending plates 54 and 54', with each portion being provided with spring contacts Sill-56d, respectively, projecting transversely, from the plates 54 and 54. The contacts SGa-iid on each plate 54 and 54' are normally biased in a direction to engage longitudinal conductors or busses 51 and 51, respectively, which are insulatingly mounted in a spaced relation on on the plates 59 and 54. Although only two condenser portions are shown for each switch Tia-21d, it is to be understood that any number may be employed depending upon the particular control circuits in the tuning system; additional portions being readily provided for by the assembly of additional plates Stand conductors 51. The end of each spring contact Sill-55d (Figs. 1 and 2) is of substantially T-shape to provide for their dove tail engagement, in a well known manner, in corresponding T-shaped apertures Sic-55d formed in flat insulating members 58a-58d, respectively, an insulator being provided for each tuning switch Tia-21d, and being adapted to efiect a concurrent operation of corresponding spring contacts. Each insulator 58a58d is maintained in following engagement with its respective armature 2211-2211, by the normal tension of the contacts 56a-55d, movement of an cause in the open position of the a-rmatures the armature byits corresponding magnet providing for a movement of the associated contacts-into contacting engagement with the conductors 51 and 51'. i

The power relay 24, as is best seen in Fig. 4, in-. cludes spaced insulating members 59 and 59' which are separate from but in alignment with the plates 54 and 54 previously described; the members 59 and 59' being attached to the bent portion 33 of the mounting plate 32. Each member 59'and 59 is provided with a pair of stationary contacts Bi! and corresponding spring contacts 62] being normally tensioned for engagement with the contacts Glf. The contacts 62] are in dove tail engagement with a flat insulating member 63f which provides for a concurrent operation of all of the contacts 62] and is adapted for actuation by movement of the armature 22f; the contacts 62! maintaining the insulator 83f in following engagement with the armature 22f in a manner similar to that previously described in connection with the. insulators 58a58d for the tuning switches Tia-21d.

The closed positions of the armatures for the tuning switches Tia-21d and power relay 24, as

maintained by the latch plate 39, occurs after contact has been effected between the contacts Sta-56d and conductors 51 and 51, and contacts EU and iii], respectively. The insulators 5811-580! and 63] are thus fioatingly supported between their corresponding armatures and spring contacts, so that all of the tension in the contacts Mia-58d and 62) is utilized in effecting an ellicient contact engagement with conductors 51 and 51', and contacts 83], respectively, and is not lost in urging the insulators against their corresponding armatures.

' In the practice of this invention it is contemplated that-the power relay 24 be operated concurrently with each of the four control switches Tia-21d. Operation of one of the control switches, such as 2111, effects an energization of both the magnets Ma and Zlf so that their respective armatures 22a and 22f are moved into an engaging position with the lip portion 43 of the interlock member 39. On operation of a second control switch, such as 211), the lifting of the latch plate 39 by the armature 21b effects a disengagement of the armatures 22a and 22f to provide for a closing only of the control circuit controlled by the switch 271) and the power relay 24. Since the power relay 24 is energized concurrently with each of the magnets for the tuning switches Tia-21d raising of the interlock 39 by movement of the armature 217.; does not effect any opening of the power relay, the armature 22f remaining in a contact position with the magnet Zif during the lifting of the latch 39. The armature 22c for the trip or release relay 26, as shown in Figs. 3a and 4, is formed with a bent end portion Me so that upon its actuation by the magnet He, the bent portion 64c acts to pivot gapbetween the armature and pole pieces is the maximum, and the magnetic force on the armature is correspondingly small. By virtue of the pivotal support 01' each armature, on a corresponding flnger 3i but small frictional losses are encountered in the mechanical movement of the armature so that with the spring forces at this position supplying the minimum resistance to movement of the armature, a very emcient application of a small magnetic force can be obtained. Furthermore, the mounting position of the spring contacts in the switches is such that there is not only the initial helpful-tension, but

in closed position the contacts are still under pressure and provide a good electrical contact without the application of a large pulling force 'by the armature as is often necessary in the prior relay and switch devices. This spring balancing oi the armatures, when in their'opened positions, and the consequently small magneticforce necessary to operate the, armatures. makes it possible to use relatively small magnets. Since most A. C. magnets are big clumsy devices the utilization of a small A. C. magnet effects an appreciable reduction in the cost of the tuner as compared to prior devices. The magnets are adapted for either A. C. or D C. application, in the usual manner, by a shading of the pole pieces '25a-25f. Since the magnets for the. power and release relays and for all of thetuning switches are the same the magnets used in the tuner may be completely standardized to effect a further reduction in the commercial cost of the tuner.

The operation of the above described tuning device is best understood from the circuit diagram shown in Fig. 17 in which the. tuning switches 21a to 21d, inclusive, are indicated in controlled association with push buttons l to 4, inclusive, respectively. Power for the control circuits is illustrated as being obtained from a suitable A. vC. supply, which is inductively connected to the circuits through suitable trans formers, the power transformer H supplying energizing current to the magnets Ila-2|}, and the transformers 12, I3 and I4 supplying energy to the radio heater circuit I6, and to the filament and plates of the rectifier 11, respectively. On

actuation of the push button I for the tuning switch 210. the circuit for the magnets Ma and 2H is momentarily closed, the current from the transformer H flowing through conductor 18,

1 push button I, coil 2ia,' conductor 19 and coil the latch 39 sufficiently to release all previously closed contacts without itself eilecting any latching or holding engagement with the latch 39.

2U, back to the transformer through conductor 8i. Energization of coils Na and 2if actuates armatures 22a and 22] into latching positions with the latch 39 so that upon release of the push button i, and consequent de-energization of the coils Zia and 2!), the armatures 22a and 22f are retained in a closed position with their respective coils. Actuation of the armature 22a provides for a movement of the insulator member or Bakelite bar 58a to permit contact of the spring contacts 56a with-the conductors or bus'ses 51 and 51, which are in electrical circuit with the tuning circuits of the radio receiving set (not shown). The actuation of the armature 22f for the power relay 24 permits a movement of the Bakelite bar 63} to provide for an engagement of the particular station identified by the push button I, which station will be heard so long as sake of simplicity.

the armature 22a is retained in its closed D sition.

It is now desired to tune in the station identifled by push button 4, it being understood that a similar operation would also be effected by actuation of the push button 2 or 3. On closing of push button 4 the circuit for the tuning switch 21d is momentarily closed from the transformer 1i through conductor 10, push button 4, coil 2 Id, conductor I9, coil 2|], and back to the transformer II through conductor 8i. Movement of the armature 22d to its latched or closed position effects a lifting of the interlock 39 to provide for a release of the armature 22a therefrom, the armature 22 being retained in its closed position by virtue of the energization of coil 2, whereby the contacts 62; of the power relay 24 are all maintained in a closed position. The release of armature 22a provides for a disengagement of the contacts 56a from the conductors 51 and 51' while movement of the armature 22d into a closed position provides for an engagement of the contacts 5611, with the conductors 51 and 51'. The tuner is thus conditioned to provide for reception from the station identified by the push button 4, as shown in Fig. 17.

During the tuning operation a momentary muting of undesirable signals is obtained by the closing of contacts 84 and 86 which are mounted in a normally opened-position on an extension lla for supporting finger 4i for the interlock or latch plate 39 (Figs. 1-4)- The contacts 84 and 86 may be connected, in a well known manner, in the muting circuit of the radio set over biasing tubes in the amplifying circuit to give a cushioned effect so as to substantially eliminate any appreciable noise in the speaker. The mounting of the muting contacts 04 and 86 adjacent to the latch plate 39 provides for this muting effect Whenever th plate 39 is pivoted by one of the armatures 2Ia-2If during switching from one tuning circuit to another. It is quite evident that the muting occurs only momentarily because the latch merely pivots from the full line position of Fig. 4, to the dotted line position and returns immediately.

Radio reception is turned off by pressing the off button, which closes th circuit for the release relay 26, the circuit from the transformer II being comprised of the conductor I8, the of! button, conductor 87, interlocking switch 02, conductor 88, coil 2Ie and conductors 09 and 8|. Energization of the coil 2 he provides for an actuation of the armature 22c which acts only to raise the latch plate 39 to release armatures 22d and 22} from their closed positions. All of the contacts 56d and 62f are thus moved to their open positions and the armature 22c, upon release of the off push button is returned to its initial position by th action of its corresponding spring 388. The radio set is thus entirely shut down on operation of the off push button. The later tuning in of a desired station is obtained by actuation of one of the control push buttons 1-4, in the manner above described.

Referring to Figs. 5 and 6 the tuner illustrated includes a plurality of tuning'switches 86a-86d, each of which is comprised of a plurality of contact switches Bio-81d and "er-88d, and a. relay mechanism such as 0904911 for operating the contact switches. A suitable base plate, electronic tubes, transformers, capacitors, inductors and the like are of course provided but will not be enumerated in detail here for the The arrangement of tubes, tuning apparatus, switches, and relays is such that each amplifier sta8e may be connected with any one of a plurality of circuit tuning elements by the action of the relays. The relays are inturn arranged so that the operation of any one relay brings into action a co-ordinated set of circult elements specifically adapted to the purpose to which the relay is devoted, as for example an entertainment program via a wire line, or via radio, or a television program via short wave radio.

Each relay lid-00d comprises an insulating rotary shaft 920-0211 which carries the rotary contact switches, Tia-81d and "it-00d; the contact switches being operated by electromagnets such as are shown at 00a, 96b, and Ne and corresponding armatures such as 91a, 01b, and 910, respectively. An armature is shown in open position at 91c and in closed position at 91b, being held closed by latch 99b. Each amplifier stage may be provided with one or more conductors or busses as IOI, through which connections may be made to the tuning elements associated with that stage, via the switches; the busses being suitably supported on insulating bars I00. The busses and switches for each stage may be grouped in suitabl shielded compartments as indicated at I 02, the shields being shown at I 03. The shaft of each relay, as 92a, may carry as many sets of contacts as required to perform the switching operations necessary to connect and tune the circuit associated with that relay. The contacts may be constructed in a great variety of ways depending upon the service to be performed. production methods, etc. The switches, busses and tuning elements are thus completely isolated when the switches are open, avoiding capacity effects and interactions between circuits. The switches 8'Ia0ld may be used where a single break with nominal stray capacity coupling is satisfactory. Each switch such as 81d includes a. flexible leaf contact I04d which is moved out of contacting engagement with a conductor such as IIlI as shown in Figs. 6 and 10 by a relatively stiff actuating conductor member I06d, the contact I 04d and conductor l06d being suitably attached to the shaft Md. The member I06d is provided at its free end with a pig tail lead for completing the tuning circuit. When the contact is in the closedposition shown in .Fig. 10, the separation of the member I06d from the leaf spring contact I04d provides for the exertion of a definite pressure by the spring on the bus IM to effect an efficient contacting engagement. A switch such as 081) provides for momentary connections between busses I05 and H0 in the "fader circuit discussed further below; the switch being shown in detail in the changed positions illustrated in Figs. 7, 8 and 9..

The switch contacts I06b and I0Ib for connection with the conductors I05 and H0, respectively, are provided at the ends of a substantially U-shaped spring contact member I08b which is adapted for movement by an actuator member I091), the actuator and spring member being suitably secured to the rotary shaft 92b. The spring contacts I05!) and I0lb effect a momentary crossconnection between bars I05 and I I0, as shown in Fig. 7, whenever any relay is either opened or closed, thus providing momentary muting during relay operation.

The relay arrangement includes a mechanical interlocking system which provides for holding the relays closed after they have been set by electrical impulses of short duration. When the operating coils of any relay are energized the switches attached to that relay are closed and locked and all other relays are opened automatically. This is arranged by providing each relay with a latch, as illustrated at 99b for relay-99b which is shown closed, and at 990 for relay 890 which is shown open. Release relay H2 is mechanically connected with the latches of all relays through release bar I I3. anism I I4 interconnects release relay H2 and release bar H9 in such a way that an impulse to relay H2 moves the bar H3 upward thereby tripping all relay latches and then immediately permits bar H3 to return to its original position. The release relay H2 comprises two electromagnets H9 and H1 and an armature H8 which is pivoted to rotate on pin H9. A trip arm III is attached to the armature and rotates with it about pin H9 as an axis. Spring I22 holds the rotating elements in the position illustrated" against the'stop I23 when the magnets are not energized. When current is applied to electromagnets H6 and H1 armature H8 rotates clock wise, carrying with it trip arm I2I. The outer end of the trip arm I2I engage with latch H4 which is attached to the bar I I3 through the pivot I24. Bar H3 is pulled upward as viewed in Fig.

6, by the rotation of the trip arm I about the pivot H9. The outer end of the trip arm -I2I swings in an are about the pivot H9 as shown by the dotted line I26. Due to this curvature, after a few degrees ofrotation, the outer tip of arm I2I slides from the outer tip of latch H4 to disengage the two members. Spring I29 then pulls bar H3 downward against the stop I21. Bar H3 may slide in grooves or may be suspended on rotatable arms as I28. When the magnets H6 and II! are de-energized, spring I22 pulls trip arm 'I2I back to the position illustrated in Fig. 6. Latch arm H4 which is pivoted to bar H3 at I24 is pushed out of the way by the tip of arm I2I as it passes. After this the spring I29 pulls the latch H4 back against the stop I3I and trip arm I2I and the latch H4 are in position for another cycle of operation. This permits any main relay, simultaneously or thereafter energized, to be latched shut as shown accomplished with respect to latch 99b. Any relay not energized will be left open, as is the case with respect to relay 890. It is thuspossible to set any relay,

and release any previously set relay by a single impulse of short duration. To this end, the operating coils of the release relay H2 may be connected in a return circuit common to the .oper-' that the response characteristics may be adjust- A trip or release mechcated at I33.

ed to the specific conditions of operation of that channel. Band pass action may be obtained in any set of circuits by staggering the tuning of the element comprising the I amplifier stages thereof, introducing damping if required by use of either fixed or variable resistors, either in series or in shunt with tuning elements.

The operating circuit for the tuning apparatus in Figs. 5 and 6 is illustrated in Fig. 18, the controlimpulses for operating the various relays being of short duration; the control current source being indicated at I32 as comprising a rectifier and/or transformer with the power supply for the radio set (not shown) being indi- The tuning switches 86a-89d are shown as being operated manually by push buttons 1-4, inclusive, respectively, although it is to 'be understood that the switches may be readily adapted for operation by remote control or suitable clock mechanism. In the operation of the circuit let it be supposed that the station identifled by push button I is to be tuned in. Operation of the push button momentarily closes the control circuit from the rectifier I32 through conductors I34 and I360, push button I, conductor I3Ia, contacts I38a, coils 96a, conductor I39, and

effect an opening of all previously closed tuning switches, by releasing the previously closed relay mechanisms.

have a single tuning inductor and a plurality of adjustable tuning capacitors which may be connected successively to the inductor by the relays for tuning in various channels or stations. In other instancesa plurality of tunable circuits, each complete in itself, may be provided. The circuits may be arranged singly or in coupled pairs with or without band pass characteristics. If circuits in coupled pairs are used the coupling and damping may, if desired, be adjustable so On energization of the coils or magnets 9611, the latch 99a is moved into its closed position with the armature 91a, the movement of the armature 91a acting to rotate the shaft 92a to effect a closing or the associated circuit switches 81a and 91a. and an operation of the switch 8841. Closing of the switch 81a closes the circuit of the power relay I4I across conductors I I42 and l43a, switch 810', conductors Will and I46, power relay coil I4I and back to the rectifier through conductors I48 and I34. Energization of the coil I41 operates armature I48 to close the interlock contacts I49 and the power supply contacts I49, whereby current is supplied to the power source I33 for the radio set, (not shown). The interlock contacts I49 operate to open the circuit of the off bus as will be explained. This.

refinement prevents the release relay H2 from clicking in the event off impulses are passed when the set has already been turned off, as in cases where the buttons I-4 are actuated by a clock mechanism. A further refinement which may be desirable in some 'cases comprises the interlock contacts I38a-I38d which are introduced in series with the relay closing coils Sta-96d, respectively. These contacts are preferably arranged to open after the associated relay has been latched closed, thereby opening the operating circuit of that relay. This refinement prevents the relay drawing current or clicking after it has been closed. The tuning of the particular circuit is thus substantially concurrently obtained with the turning on of the radio set by actuation of the push button I, the coils H6 and H1 acting only to operate the release relay H2 and the coils 96a the tuning switch 860.

With the tuner thus conditioned by button I, it is now desired to tune in the station controlled by button 3, which operates tuning switch 860. Actuation of push button 3 closes the circuit for the release relay H2, and the relay mechanism 890 through conductor I34, and I380, push button 3, conductor I310, interlock contacts I380, coils 96c following description.

and conductor I39 to release relay coils H6 and III, and the rectifier I32. The release relay II2 operates to release the latch 990 from engagement with the armature 91a whereby to open all of the switches 81a, 81a, and 66a and hence the tuning circuit controlled by push button I. Energization of the coils 960 conditions the switches 610 and for a tuning in of the new station in a manner similar to that previously described in connection with the operation of push button I.

In order to cushion surges in the amplifier and speakers when a shift of stations is made, a set of interlock contacts, as indicated at 88a-88d is provided. These contacts cause a momentary cross connection to be made between busses I65 and I III for momentarily muting the output of the receiver in any desired manner. For example the gain of the radio frequency amplifying and volume control stages may be momentarily reduced, causing one station to fade out and the other to fade In the event it is desired to turn the radio receiver oh the "011 button is operated. This operation of the "off button closes the-circuit from the rectifier I32 through conductor I94, the off button, conductor I5I, contact I49, conductor I52 and coils H6 and H1 backto the rectifier. Energization of the coils H6 and H1 operates the release relay II2 to release the latch 99c whereby to open the tuning switch 960, opening of contact 610' effecting a de-energization of coil I41 and a. consequent opening of the contact I49, to shut off the supply current to the power source I33 for the radio set. The release relay I I2 is thus seen to be operated to open previously latched relays 99a9 9d whenever a shift is made from one station to another and also whenever the o signal is given. I

A further modification of the invention is shown in Figs. 11-16, inclusive. Numerals I660- I52d indicate four of a plurality of tuning switches which are used for making the connections necessary to tune the receiver for various channels or stations. Four banks of adjustable tuning capacitors are indicated at I64 to I51 inclusive. Since all of the tuning switches such as I53a-I53d are of similar construction only, switch I530 will be referred to in the Each tuning switch as I530 comprises an electromagnet, as shown at I590, Fig. 15, and an armature, I6I0, which serve to operate a plurality of contacts through the medium of an insulating tie bar I620. This figure is a sectionalong line I6-I6 of Fig. 12 taken so 'as to show in elevation the operating mechanism and contacts of relay I660, which is shown here in closed position. Four sets of contacts, I630, are provided for connecting into tuned circuits the tuning capacitors as I64, I66, I56 and I51, associated with the channel or station assigned to this particular relay. The transformers of the amplifier stages whose circuits are thus tuned may be housed in suitable shields as indicated at I64, Fig. 11, and a bank of amplifier tubes may be placed adjacent thereto as indicated at I66. The switches and capacitors associated with each stage may be housed in a shielded compartment as indicated at I61, Figs. 11 and 15. Stationary insulating bars I680, Fig. 11, and I690, Fig. 15, may be provided for holding the stationary contacts in the required positions, cooperating with the insulated tie rods, as I620 and I620, which serve for actuating the moving contacts of the several switches. Further details of these contacts,

rods, and bars are shown in Fig. 16 representing a perspective view of contacts I690 and associated tie rod I620 and bar I660.

Each switch, as I660, comprises two sprin leaves as I690 and "I0 which carry contacts as I and I160. Spring leaf I690 is dovetailed into-the insulating tie rod I620 as illustrated at I140. Spring leaf I690 therefore moves with rod I620 whenever the latter is actuated by armature I6I0 (Fig. 15). Armature I6I0 is pivoted at I690. Energization of the electromagnet I690 attracts armature I6I0 to the magnet and shifts the bar I620 to the left as shown in Fig. 15. This moves all of the switch leaves I690 which are dovetailed to the bar I620 to the left and closes all of the associated contacts as I120 and I190 thereby connecting into the circuit the tuning elements controlled by these switches. Latch I engages the armature I6I0 and holds the switches closed after the magnet is de-energlzed. When the latch I160 is tripped, as described hereinafter, the spring leaves I690 of the switches pull tie bar I620 to the right until the armature I9Ic rests against the stop I110. In order that this motion may open the contacts as I120 and I130, spring leaf "I0 is provided with a projection I190 which engages with a fixed stop I190. This stop is formed by a notch I9I0' in the stationary insulating bar I690 (Fig. 16). Leaf "I0 is free to move to the left when leaf I690 moves to the left for bringing contacts I120 and I190 into closed position. When leaf I690 moves to the right, the motion of leaf "I0 is limited by the projection I engaging the stop I The notch I6I0 thus positions leaf I1Ic so that motion of the tie bar I620 may open and close contacts I120 and I190. The pressure applied to the contacts is determined by the tension of the spring leaf "I0 and this pressure is applied to the contacts the moment they are closed, being approximately the same as the pressure exerted by spring leaf I1I0 against stop I190. The notched bar I690 therefore serves to determine the position of its associated spring leaves as "I0, and the construc tion permits definite contact pressures to be maintained as well as definite positions. The construction also permits the moving switch elements as spring leaf I690 to serve as the spring for actuating armature I6Ic pulling it away from the magnet I690 when tie-energized The dovetail and notch construction of insulating bars I620 and I690 permits the use of low cost stampings and this construction likewise facilitates the assembly of the multiple switch parts.

In addition to the switches for performing tuning operations. each relay may carry as many auxiliary switches as needed. In Figs. 11 and 15, a three element auxiliary switch I920 is provided for operating the biasing circuits which provide for fading to give quiet operation during the shift from one station to another as discussed in connection with switches "(c-69d, Fig. 18. A second auxiliary switch 1660 serves to energize the power supp y contactors, as shown at I49 and I49 in Fig. 18. A third set of auxiliary contacts indicated at I640 may be arranged to function in cooperation with the latch I160, Fig. 11, providing means for opening the control circuit or the tuning switch I660 after it is latched closed, as indicated at I360- I39d, Fig. 18, when such an arrangement is considered desirable. Other arrangements of contacts for other purposes may, of course, be pro vided as required. It will be evident that the construction shown provides great flexibility in Relays which are to be held closed after receiving a closing impulse may be provided with latches as illustrated at IIGa-IIGd, Figs. 11, 12, and 15. Figs. 12 and 14 show also the release mechanism comprising electromagnet I86, armature I81, and linkage I88 interconnecting the armature I81 and trip bar I88. Linkage I88 may take a variety of forms. As shown in Fig. 14 it comprises a link and bell crank so arranged that bar I89 is momentarily lifted to trip the'latches whenever the trip coil I86 is energized. Bar I88 is then allowed to drop again even though the relay is still energized. This permits any relay holding means to a condition for holding the other selected relay in a closed position.

2. Electrical apparatus including a plurality o relay units, means for selectively closing a relay unit, mechanical means operatively associated with said relay units and adapted for holding a selected relay in closed position, means for releasing a held relay simultaneously" with the energization of a selected relay unit, means for restoring the holding means to provide a holding position with the energized relay unit to hold the same in an operated position, and tension means for returning said released relay to an open position.

receiving an impulse to be closed and latched while previously closed relays are released.

Figs. 12 and 13 indicate arrangements whereby contacts as If, for handling power circuits may be applied to the relays. Such power contacts may be used also with any of the tuning relays to close the power circuit in place of using a separate contactor therefor. This construction may be used also to make a power circuit contactor from standard relay parts. Such a contactor may be provided with interlock contacts similar to contacts I830, and a latch similar to IIBc. if d'esLred. An electrical interlocking and latching system may be used in place of the mechanical latches illustrated by I160 and release bar I89 if' desired.

Busses, as I92-I95, inclusive, may be provided for interconnecting the various interrelated switches and tuning elements.

The invention is thus seen to provide for a compact, efficient, and low-cost tuning apparatus in which a continuous bus or conductor serves as a common connector and contact in all of the tuning circuits. There is also provided interlocking means which is adapted to hold closed the last actuated contacts and to release all previously closed contacts; with the circuit closing magnet operating and latching means. The magnets for operating the tuning circuits and the power and release relays are of similar construction and readily adapted for use in either A. C or D. C. circuits. All of the contacting switch elements are adapted to provide for a definite contacting pressure in their closed positions to eiiecta positive and eiiicient closing of all of the tuning circuits. Although the invention has been described and illustrated with reference to push-button control, it is to be understood that it is equally adaptable for operation by remote control or by a clock mechanism.

It is to be understood also that only preferred embodiments of the invention have been illustrated and described herein and that modifications thereof can be made which are within the full intended scope. of the invention as defined by the appended claims.

I claim: I

1. Electrical apparatus including a plurality of relays, means for selectively closing said plurality of relays, latch means for releasably holding a selected relay in closed position, means acting on said holding means to release said held relay simultaneously with the energizing of a selected 3. Electrical apparatus including a plurality of relay units, tension means for retaining said relay unit in an open position, means for selectively closing a relay unit against the pressure of said tension means, each of said relay units including an armature, and. means for releasably lockingsaid armature in an operated position,

. said locking means being actuated simultaneously of relays, means for releasably holding a selected relay in closed position, a trip mechanism operatively common to all of said relays for actuating said holding means to release a held relay, means for energizing said trip mechanism simultaneously with the energizing of a selected relay to release any held relay, means for immediately restoring the holding means to a holding condition to hold the selected relay in a closed position, and means for returning said released relay to an open position.

5. Electrical apparatus including a plurality of relay units, means for selectively closing a relay unit, mechanical means for eachrelay unit for holding a selected relay in closed position, a single trip mechanism common to all said holding means and mechanically connected therewith,

means for energizing the trip mechanism simultaneously with the energization of a selected relay unit, and means acting on said trip mechanism to cause it to momentarily release an operated holding means with all of said holding means being immediately restored to a position at which a holding means corresponding to a selected relay unit acts to hold the same in operated position.

6. Electrical apparatus including a plurality of relay units, a single trip relay unit electrically common to all of said relay units, movably mounted mechanical means operatively connected with said single trip relay unit and mechanically common to all of said plurality of relays,

relay, and means for immediately restoring said holding means operatively connected with said movably. mounted mechanical'means and acting on each relay individually, means for selectively energizing said relay units and substantially simultaneously with the energization of a selected relay unit energizing said single trip relay unit to cause momentary actuation of said mechanical means to release any held relay units, and means for substantially immediately thereafter restoring said mechanical means to a position at which said selected relay unit may be held in operated position by said holding means.

7. Electrical apparatus including a plurality of relays, each of said relays including an electromagnet and an armature, means for selectively operating said armatures, latching means for each armature for mechanically latching a selected armature in operated position, a single unlatching means mechanically common to all said latching means, a single relay for operating said single unlatching means, and circuit means for substantially simultaneously energizing a selected relay and said single relay for operating said single relay to unlatch any latched armatures on the relays, and with said unlatching means beingdmmediately returnable to idle position to permit the latching means for a selected relay armature to latch such armature all during merely a momentary energization of a selected relay.

8. Electrical apparatus including a plurality of relay units, with each of said relay units including an electro-magnetic unit having an armature, means for selectively operating said armatures, interlock means for mechanically locking a selected armature in closed position, and a single trip means operatively common to all of said relay units acting on said interlock means for opening said closed armature concurrently with the operation of another selected relay.

9. Electrical apparatus including a plurality of selectively operated relays, each of said relays including a rotatable shaft, electric-switch means supported on said shaft, an armature secured on said shaft, an electromagnet having the poles therefor positioned with reference to said armature in such a manner as to accomplish rotary movement of said armature upon energization of said electromagnet, a plurality of latching elements, with one of said latching elements for each of said armatures to latch a selected armature in operated position, means for unlatching a latched armature including a movable member common to all of said latching elements, and means for moving said movable member upon energization of any one of said relay electromagnets to simultaneously move all of said latching elements to unlatch any armatures latched, with said member being restored substantially immediately to a position at which the armaits associated armature, means common to all of said latches for moving the same, said means inture for a selected energized relay may be latched in operated position.

10. Electrical apparatus including a plurality of selectively operated relays, each of said relays including a movable armature, a pivoted latchw common to said relay units for latching a selected armature in an operated position, and means for unlatching a selected latched armature before 11. A pre-assembled control unit for an electrical system including a plurality of selectively energized relay units, a power relay common to all of said relay units, means common to said power relay and relay units for holding said relay and relay units in an operated position, with said power relay being energized simultaneously with each of said relay units, and a trip relay operable to move said holding means out of holding position with said relay units and power relay.

12. Electrical'apparatus including a plurality of relay units. each of said units including a mova'ble armature, and a pivoted latch for each of said relay units for latching engagement with eluding a slidable elongated member having a plurality of projections with a projection corresponding to each of said latches for engaging said latches upon movement of said member in one direction, a trip on said member, a trip relay having movable means for engagement with said trip to move said member in said one direction to a position at which said movable means becomes disengaged from said trip, and means for moving said member in a direction opposite to said one direction to an idleposition.

13. In electrical apparatus as defined in claim 12, with said trip relay comprising an electromagnet having a pair of spaced apart pole pieces, an armature pivoted intermediate said pole pieces for pivotal movement into engagement with both pole pieces upon the energizing thereof, with said armature carrying said movable means for engagement with said trip.

14. Electrical apparatus including a plurality of relay units, each of said units including a plurality of switches, a single movable member common to all of said switches and acting to close the same, means for moving said member, in-

cluding an armature pivoted intermediate its ends and connected at one end to said member, an electromagnet acting on the other end of said armature to attract the same thereto, and pivoted latch means for engaging said armature and .contacts acting to move said member in the other direction upon the de-energization oi-said electromagnet, and stationary insulating means having a stop portion corresponding to each of said pairs of switch contacts for limiting the movement of the other switch contact in each of said pairs when said member is moved in such other direction.

16. Electrical apparatus including a plurality of relay units, each of said units including a frame, a stationary electromagnet mounted thereon, a pivoted armature mounted on said frame adapted to be attracted to said electromagnet, a plurality of switches for each of said relay units, each of said switches being independently mounted upon said frame and including a pair of switch contacts, a movable member connected with said armature and movable therewith and being operatively connected with one of the switch contacts for each of said plurality of switches, a stationary stop bar mounted on said frame having a stop portion corresponding to each of said switches, with the other of said contacts for each switch adapted to engage a corresponding stop portion on said bar upon movement oi. said member in one direction to separate said contacts and open an electrical circuit through each switch, with said contacts in each switch adapted to be closed upon movement of said member by said armature in the opposite direction.

17. A preassembled control unit for an electrical system including a plurality of selectively energized relays, a power relay, each of said relays and power relayincluding a movable armature in operative association with a plurality of control switches, with said power relay being energized simultaneously with the energization of a selected relay, latching means for lockingly engaging said armatures to provide for a holding of said power relay and said selectively energized re lay in a closed position, each of said armatures on energization of its corresponding relay acting to move said latching means to open all previously closed relays before effecting a locked engagement with said latching means.

18. A pre-assembled control unit for an electrical system as defined in claim 1'7, having a trip relay including a movable armature, said trip relay being adapted for energization independently of said relays and power relay, energization of said trip relay effecting a movement of its associated armature to trip said latching means to open said previously closed selected relay and said power relay, with said trip relay remaining open after said tripping operation.

19. Electrical apparatus including a plurality of relay units and a conductor common to all of said units, each of said units including a movable armature and a control switch in' operative association with said armature, latching means for lockingly engaging said armature to provide for a holding of its associated relay unit in an operated position, said control switch including a spring contact arm normally tensioned to efiect contact with said conductor, an insulating member arranged between said contact arm and armature, the spring tension insaid arm being adapted to effect a following engagement of said member with said armature, said armature in an unlatched open position co-acting with said memher to hold said contact arm out oi. engagement with said conductor, and said member on latching engagement oi said armature in a closed posi- 'tion being floatingly supported between said contact arm and armature toprovide for the exer tlon of a definite spring pressure on said conductor by said contact arm.

20. Electrical apparatus including a plurality of relay units, each 01 said units including an armature and a plurality of switches, a single movable member common to said switches and acting to close the same, means for moving said member including said armature, said armature being pivoted intermediate its ends and in operaattract the same thereto. and pivoted latch net providing for a flush engagement of said magnet and armature, and a control switch arranged for operation in response to movement of said armature, with energization of said magnet moving said armature to provide for a closing of said switch.

22. Electrical apparatus including a plurality of relay units and including a supporting frame of substantially L-shape for a plurality of operating magnets for said units, with said magnets being arranged in longitudinal alignment on said frame, and one of said frame leg members being substantially co-extensive in length with said magnets, a plurality of armatures corresponding .to said magnets pivotally supported adjacent the end of said one leg member, a longitudinally extending conductor common to all of said relays, a longitudinally extending insulating member common to all of said relay units, each of said armatures being movable between said insulating member and its corresponding magnet, latching means common to all of said relay units adapted for locking engagement with'said armatures to provide for a holding of said relay units in an operated position, said latching means being pivotally connected to said supporting frame, with each armature being operable to move said latching means to effect an opening of all previously closed relay units prior to effecting a locking engagement with said latching means, a controlv switch for each of said relay units including a spring contact arm normally tensioned to effect a oi relays, means for selectively closing said plurality oi relays, means common to said plurality of relays'for releasably holding a selected relayv in closed position, means acting on said holding means to release said held relay simultaneously with the energizing of another selected relay, means for immediately restoring said holding means to a holding condition to hold said other selected relay in a closed position, and means for means for engaging said armature and holding support of said armature adjacent said prolection, said projection on energization of said magreturning said released relay to an open position.

:24. Electrical apparatus including a plurality of relays, means for selectively closing a relay unit, latching means common to all oi said relay units, a portion on each or said relays mov able. therewith into locking engagement with said latching means to hold a selected relay in a closed position, with the portion of said selected relay'acting on said latching means to release a previously held relay simultaneously with the energizing of said selected relay, means for restor open position.

HAROLD F. ELLIOTT. 

